The analysis of pharmaceutical metabolites within the human body is important in the development of pharmaceuticals. Glucuronides are eliminated as detoxifying metabolites of pharmaceuticals. However, the possibility that some could turn into reactive metabolites and exhibit toxicity has been pointed out. For example, among the glucuronides, acyl glucuronides, which are ester glucuronides, present the possibility of becoming reactive metabolites and causing drug-induced liver damage (Nonpatent Reference 1).
Accordingly, while it is necessary to evaluate the safety of the glucuronides themselves, site-specific glucuronidation is extremely difficult by organic synthesis methods. Accordingly, there is great need for a method permitting the efficient producing of a targeted glucuronide using enzymes, microorganisms, and the like. Currently, the preparation of glucuronides using animal liver-derived microsome fractions is being practiced. However, the productivity and the scope of applicability are inadequate. Human glucuronosyl transferase employing an insect cell system is already commercially available. However, use as an enzyme source in the preparation of glucuronides is impractical from a cost perspective.
The present inventors constructed the expression system of glucuronosyl transferase employing Saccharomyces cerevisiae that has been employed thus far, and proposed the enzymatic synthesis of glucuronides that are pharmaceutical metabolites employing it as an enzyme source for glucuronide preparation (Nonpatent Reference 2).
Recently, Dragan et al. (Nonpatent Reference 7, Patent Reference 1) constructed a system producing glucuronides from Schizosaccharomyces pombe (S. Pombe) cells expressing UGT employing S. Pombe. 